Non-invasive measurement of blood glucose level

ABSTRACT

A non-invasive device for measuring blood glucose levels comprises an enclosure with a cover and dual openings, wherein the enclosure is covered with a transparent material (e.g., glass or plastic); at least two test cards arranged at specified distances and positioned within the enclosure; an illuminator and a conical light reflecting surface for casting a beam on the test cards. Light from one test card is reflected through one of the dual openings to sensing receptors of one eye. In order to enable the part of a diffuse beam reflected from the second test card made parallel within 10° to fall on the sensing receptors of the second eye, the enclosure is provided with a tubular prism covered with a closing plate having an opening at a first end while having an opening covered preferably with transparent material at a second end.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims benefit to International ApplicationPCT/CA02/01678, filed Oct. 31, 2002, said International Applicationclaims priority from Hungarian Application P0104610, filed Oct. 31,2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a non-invasive device for determiningblood glucose levels through the measurement of colour perception.

2. Description of the Prior Art

Diabetes mellitus is a disease which afflicts millions of individualsthroughout the world. It is a chronic metabolic disorder that ischaracterized by a high blood glucose concentration, otherwise known ashyperglycaemia. Elevated glucose levels are brought about by insulindeficiencies and/or insulin resistance. Hyperglycaemia occurs as aresult of uncontrolled hepatic glucose output, in addition to areduction of glucose uptake by skeletal muscle. If the threshold forrenal glucose re-absorption is exceeded, a number of negativephysiological outcomes can occur including, an increase in urine glucoselevels and osmotic diuresis, a condition which leads to dehydration andexcessive thirst. As the disease progresses, individuals afflicted withdiabetes may experience damage to their kidneys retina and peripheralnerves.

As a result of the potential negative effects of the disease, diabetessufferers must take frequent measurements of the blood glucose levels,in order to monitor and control said glucose levels. Based on theresults of these measurements, individuals can alter their food intake,physical activities, and insulin dosage, as a means of regulating bloodglucose levels.

A number of methods and devices for measuring blood glucose levels aredisclosed in the prior art. However, the majority of these means ofblood glucose measurement are characterized by their invasiveness andtheir cost.

One such blood-glucose level measuring device, the D CONT Cabrio,requires an individual to perform the invasive step of pricking theirfinger in order to draw blood for testing. Puncturing of the finger canbe quite painful and can result in significant discomfort for theindividual. After blood has been drawn, a drop of blood from the fingeris applied to a test strip, which is then inserted into an electronicglucose measuring device. Upon insertion in the measuring device, achemical reaction occurs between the blood and the test strip, whichresults in the test strip changing colour based on the level of glucosepresent in the blood. Colour changes are detected by the electronicglucose measuring device and results are displayed as numeric valuesrepresentative of the level of blood glucose. In addition to theaforementioned discomfort caused by this method of testing, the teststrips used in this methodology are not always available in a sufficientquantity, and the cost of purchasing such strips can represent a largefinancial burden on the individual. Further, the purchase cost of theactual measuring device is also quite high, therefore, patients oflimited financial means may not be able to afford the device.

Non-invasive, blood glucose level testing devices have also beendescribed in the prior art, but such devices are also characterized byspecific deficiences. For example, the Gluco-Watch is one such devicedesigned to eliminate the need for invasive blood glucose testing. TheGluco-Watch is worn on the arm of a patient and is equipped; withsensors that can measure blood glucose levels at intervals of 3 hours.Unfortunately, this device is also costly to the consumer.

The present invention seeks to provide a device for testing bloodglucose levels that overcomes the deficiencies in the prior art.Specifically, the present invention provides a non-invasive measurementdevice, at a reasonable cost to the consumer.

SUMMARY OF THE INVENTION

The present invention relates to a blood-glucose level measuring deviceenclosed in a box (19) that can be opened and closed, and that has acover (39) provided with two openings (9, 12) covered with sometransparent material and is made preferably of dye-cast plastic,characterized in that at least two test cards (1, 2) are arranged atspecified distances and specified positions within the box (19), and atleast one illuminator (17) is built in the box preferably in front of aconical reflecting surface (18); in order to enable the diffuse beamthat is generated by the illuminator, reflected from the inner surfaceof the closed box (19) to illuminate the two test cards (1, 2) andreflected from one of the test cards (1) to fall on the sensingreceptors of the eye (6), the box (19) is provided with an opening (12)covered preferably with some transparent material, while in order toenable the part of diffuse beam (4) reflected from the other test card(2) made parallel preferably within 10° to fall on the sensing receptorsof the eye (5), the box is provided with a tubular prism (10) that iscovered with a closing plate (7) with an opening (8) at the one endwhile having an opening (9) covered with some preferably transparentmaterial at the other end.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the preferred embodiments of the inventionwill become more apparent in the following detailed description in whichreference is made to the appended drawings wherein:

FIG. 1 diagrammatically shows the diffuse and parallel light beamsreflected from two test cards located side by side and eyes.

FIG. 2 diagrammatically shows an embodiment of the blood glucose-levelmeasuring device.

FIG. 3 diagrammatically shows an embodiment of the present inventioncomprising a revolving blood-glucose level indicator for accommodatingseveral test cards, and further comprising a closing cover.

FIG. 4 diagrammatically shows a detailed schematic of the electriccircuit utilized in the blood-glucose level measuring device.

FIG. 5 diagrammatically shows the device formed by the invention

FIG. 6 diagrammatically shows the device composed by the invention inthe box

FIG. 7 diagrammatically shows the device in an adjustable form.

FIG. 8 diagrammatically shows a detailed side view of one side of thepresent invention

FIG. 9 diagrammatically shows a detailed side view of a second side ofthe present invention

FIG. 10 diagrammatically shows a detailed schematic of the presentinvention comprising a revolving blood-glucose level indicator foraccommodating several test cards.

FIG. 11 diagrammatically shows an additional detailed schematic of thepresent invention comprising a revolving blood-glucose level indicatorfor accommodating several test cards.

FIG. 12 diagrammatically shows an additional detailed schematic of apreferred embodiment of the present invention.

FIG. 13 diagrammatically shows an additional detailed schematic of apreferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In a preferred embodiment, the present invention provides a non-invasiveblood glucose level testing device that measures the level of bloodglucose, utilizing an optical based test.

The preferred device can be used by individuals suffering from diabetes,said individuals having to control their blood glucose level throughregular injections of insulin. In addition, the preferred device canalso be used for preventative purposes. The preferred blood-glucoselevel measuring device allows for detection of increased blood glucoselevels before such levels exceed safe physiological limits.

In a preferred embodiment, the blood-glucose level testing device isbased on the principle that fluctuations in blood-glucose levels candramatically influence eyesight. For example, during fluctuations inblood-glucose levels, because of the fact that the retina is highlysensitive to said fluctuations, the perception of an observed image andits color may be altered. As such, an individual may be able to directlyassess the extent of vision changes and estimate such changesquantitatively, using a preferred embodiment of the disclosed invention.

Experiments have shown that blood-glucose level is interconnected withcolor perception. People with different blood-glucose levels perceivethe same color differently, and if the color perception of the two eyesis changed simultaneously, the current blood-glucose level can bedetermined from this difference using Table 1, which is based onexperimental results.

TABLE 1 The sign of the color by The sign of the color by Blood-glucoselevel the color-scale 1 the color-scale 1/A (mmol/litre) S 2040-Y90RS-1080-R 3 S 2050-R S-1080-R 5 S 2050-Y90R S-1080-R 6 S 1070-R S-1080-R8 S 3050-R30B S-1080-R 12

The larger the difference between the color perception of the eyes, themore precisely the blood-glucose level can be determined. Experimentsalso showed that while watching a shade of color through a low-diameterhole with one eye, the other eye perceives a different shade. Thisdifference can be enhanced using a tube with an arbitrary bore as asmall hole, and the other end, positioned away from the eye, of the tubethe bore is reduced, for example to 0.5 mm.

The experiments performed demonstrated that, if the photo-receptors ofthe eye receive diffuse light reflected from a color object, the extentof modification in the color sensing, due to the change in theblood-glucose level, is magnified by collecting the diffuse light beaminto a nearly parallel beam. By comparing the color effects caused bythe diffuse light reflected from a color object, with those caused bythe parallel beam on the photo receptors, as well as allocating theblood-glucose level value at the time of measurement to the colordifference estimated quantitatively, and then repeating the measurementswith different blood-glucose level values, the possibility ofestablishing a blood-glucose level scale based on color sensing wasobtained. The aforementioned scale can be used to determineblood-glucose levels without requiring any blood samples and istherefore non-invasive.

Color objects, color test cards, colors projected on white cards, colorsgenerated in electric way, colors generated by means of liquid crystals,can also be used for color sensing for the purpose of blood glucoselevel measurement.

In a preferred embodiment, as described further below, a blood-glucoselevel measuring device was produced that is enclosed in a box (19) thatcan be opened and closed. The device has a cover (39) provided with twoopenings (9,12) covered preferably with transparent material (e.g.glass, plastic) and is made preferably of dye-cast plastic, where,according to the invention, at least two test cards (1,2) are arrangedat specified distances and specified positions within the box (19), andat least one illuminator (17) is built in the box preferably in front ofa conical reflecting surface (18). In order to enable the diffuse beamthat is generated by the illuminator, reflected from the inner surfaceof the closed box (19) to illuminate the two test cards (1,2) andreflected from one of the test cards (1) to fall on the sensingreceptors of the eye (6), the box (19) is provided with an openingcovered preferably with some transparent-material, while in order toenable the part of diffuse beam (4) reflected from the other test card(2) made parallel preferably within 10 degrees to fall on the sensingreceptors of the eye (5), the box is provided with a tubular prism (10)that is covered with a closing plate (7) with an opening (8) at the oneend while having an opening (9) covered with some preferably transparentmaterial at the other end.

Preferably, the test cards (1,2) paired appropriately, are fastened onthe sides of a regular polygonal prism (21) that can be rotated withinthe blood-glucose level measuring device; a positioning spring holds theprism in its proper position and the blood glucose level value isindicated by the blood glucose indicator on the dial of the turn-knob.

It is preferred that the illuminator (17) of the blood-glucose levelmeasuring device is actuated by a micro switch that is mounted betweentwo springs fastened to the base plate of the box and fastenedpreferably to the upper spring when the turn knob is rotated.

Also in preferred embodiment, the illumination required for theblood-glucose level measuring device, is provided in the form of a glowlamp. The glow lamp is operated by a push-button switch or a rotatingswitch, and the illumination is active for a pre-determined time (e.g. 5seconds) and, following this period, the illumination is disabled for aspecified time (e.g. 4 seconds). When the device is ready to be switchedon again, an indicator light is turned on. The device can be turned OFFand ON by a general switch.

In a preferred embodiment the blood-glucose level-measuring device isprovided with a supply voltage indicator.

Referring now to FIG. 1 of the accompanying drawings, there is showndiffuse light beams 3 and parallel light beams 4 reflected from testcards 1 and 2, towards eyes 6,5. During experimentation it wasdetermined that diffuse light beams 3 and parallel light beams 4,reflected from the test cards 1 and 2, respectively, were perceived asthe same color in individuals with a 5 mmol/liter blood-glucose level.For example, the colour Ral 1004 golden-yellow was perceived by both eye6 exposed to the diffuse light beams 3, and eye 5 exposed to theparallel light beams. However, when an individual had a blood glucoselevel of 8 mmol/liter, Ral 1004 golden yellow was perceived to be goldenyellow with diffuse light, while it is perceived to be of Ral 8008 olivebrown colour with parallel light. As a result, if parallel light beams 4reflected from a test card of RAL 1004 color arrive at eye 5, anddiffuse light beams 3 reflected from a test card of RAL 8008 colorarrives at eye 6, both of the test cards would be perceived to be a RAL8008 olive-brown color.

Referring now to FIG. 2 of the accompanying drawings, there is shown aview of a preferred embodiment of the blood-glucose level measuringdevice in an open state. The inner space 16 of box 19, of a preferredblood-glucose level measuring device is illuminated by the illuminator17. The illuminator 17 is surrounded by a conical light reflectingsurface 18, which directs beams of light towards the, preferably,coloured test cards 1,2. The coloured test cards 1 and 2 reflect lightthrough openings 12 and 9, which are covered with transparent material,to eyes 5 and 6. The beams of light 3 reflected from the test card 1 arediffuse, while the light beams 4 reflected from test card 2 are nearlyparallel. In other words, the reflected light beams 4 are allowed todeviate by up to 5° from the vertical. The parallel light beams 4,arrive at eye 5 through the opening 8 of closing plate 7, which coversthe end of the tubular prism 10, and through opening 9, which is coveredwith transparent, material on the box 19. In order to enhance the purityof the appearing color, it is also necessary that inner surface 14 ofthe tubular prism 110 is comprised of a material with strong lightabsorbing properties. In addition, in a preferred embodiment, the lightbeams illuminating the test card 2 are shielded with a shielding 15 madeof semi-transparent. (ie. opaque) material. Such shielding is requiredif the test card 2 has a bright surface.

Because a distance (S) of the pupils of each individual varies, theposition of the openings 12 and 9 can be adjusted by means of the ovalshaped opening 11 on the box 19. In addition, sliding plate 13 can bedisplaced and fastened, in order to ensure that the diffuse and parallellight beams can be sensed by the 5, 6 eyes. The illuminator 17 operatesonly if the electronic unit activates the LED 20. When the device isready to measure blood-glucose levels a green light on the LED 20 turnson. When the green light turns on, the 17 illuminator can be switched onand blood-glucose level measurement intiated.

It is preferred that the diameter D1, of the preferably circular openingarranged on the closing plate of the tubular prism built into theblood-glucose level measuring device, is of up to 2 mm, while thediameter D2 of the preferably circular opening covered with sometransparent material, as well as the diameter D4 of the preferablycircular opening arranged on the slide plate, and covered withtransparent material, are less than 10 mm each, and the diameter D3 ofthe tubular prism (10) is greater than or equal to the diameter D2.

Referring now to FIG. 3 of the accompanying drawings an additionalembodiment of the preferred blood-glucose measuring device is provided.In this embodiment a preferred blood-glucose level measuring device isprovided with a revolving blood-glucose level indicator and lockablecover plate 38. Several test cards 22, 22′, can be fitted to adecahedral regular prism 21, which can be rotated and is built into thelockable box 19. Paired test cards 22, 22′ are fastened to the sides ofthe prism 21. It is preferred that the test cards not in use during theblood-glucose level measurement are covered by two cover plates 23, 24in order to eliminate their disturbing effects. The regular prism 21 canbe rotated using turn knob 25. The rim of the turn knob 25 is providedwith a dial 26 suitable for indicating the blood-glucose level. Theblood-glucose level is shown on the blood-glucose level indicator 27.Turning the regular prism 21 by a unit angle, its positioning is ensuredby the positioning spring 28.

Spring 30, which is connected to and responsible for positioning themicro switch 29, is fastened to the bottom plate of lockable box 19 byfastening element 31. Between the two springs, the micro switch 29 isarranged and is fastened to the spring 30. The lockable box 19 isprovided with dimming rims 32 arranged symmetrically. In order to ensurethe comfortable use, the preferred embodiment has an indent 33corresponding to the shape of a nose ridge. In order to ensure portableoperation, the device is provided with rechargeable batteries 36 and 27,and a connector 47 for recharging. The readiness of the device to repeatthe blood-glucose level measurement is indicated by the green light ofthe 20 LED. When the batteries 36 and 37 require recharging, a red lightor, voltage indicator 48 is switched on. The device can be switched offand on by using general switch 34. The repeated measurements can beinitiated by means of touch-switch 35. The cover plate 38 is fastened tothe box 19 by means of closing element 39, while it can be openedthrough opening hole 40. The undesired displacement of batteries isprevented fastening element 41.

Referring now to FIG. 4 of the accompanying drawings a preferredembodiment of the electric circuit of the preferred blood-glucosemeasuring device is provided. The internal illumination of theblood-glucose level-measuring device can be ensured for a specified time(e.g. 5 seconds) by means of the illuminator 17, said illuminator beingactivated by touch-switch 29 and touch-switch 35, respectively. Afurther requirement for the evaluation of blood-glucose levelmeasurement is that the re-activation of the device is prevented for aspecified time (e.g. 5 seconds) following each measurement. When thepreferred device is ready for operation, its status is indicated by thegreen light of LED 20. For the measurement of time, the monostable 42,42 or in other words timing circuit (e.g. IC of type C556), is utilized.On activating the push-button 35 or the turn knob 29 switch, bothmonostables 42 and 43 receive a voltage pulse necessary for tripping.The operating time of monostable 42 is approximately 5 seconds. Theoutput from monostable 42 drives through the power amplifier 44 and 45(T1 and T2 transistors in Darlington circuit) and the illuminator 17.The monostable 43 prevents the device from being re-started during theoperation of the illuminator 17, and for 5 seconds following operation.As a result a time cycle of 10 seconds is controlled by the monostable43, the output signal of which is fed back through the OR gate 46 to thestarting input of the timing circuits 42 and 43.

To the other input of the OR gate 46, push button 34 and the turn knobswitch 29 are connected in parallel. As a result of the operation of the46 OR gate, the timer circuit 42 is allowed to be re-started only if a10-second operation of the 43 timer circuit is completed, and either thepush-button 35 or the turn knob switch 29 is operated. The possibilityof re-starting the device is indicated by the LED 20, connected to theoutput of the timer circuit 43, that operates for 10 seconds, andfollowing the expiry of the 10-second period, it activates the LED 20.Once the conditions of re-starting are fulfilled, the LED 20 is switchedoff.

The preferred blood-glucose level measuring device can be produced atlow cost and is extremely simple to use. Further, no additionalmaterials and supplies are required for operation of the device afterits initial purchase.

FIGS. 5 and 6 show the preferred device has a color-scale (1, 1/A) andin front of that a looking appliance (5) formed to eyehole (4) whichcovers the eye (3). The (1) color-scale is composed to have a view of itwith naked eye. The tube joins to the opening of looking appliance, theinside bore of its open end is 0.5 mm.

By the one device of the invention there are two color-scales (1, 1/A)side by side and they can rotate with the adjusting knob (16). There are11 bulbs in front of the color-scales (1, 1/A) and 10 energy source, forexample penlight battery, is intended for them. The color-scales can useas artificial light for example LED.

In FIG. 7 the set with 12 set bolts by invention is formed from thetillable left (13) and right part (14) which can move around therotation axis (15). We can adjust the distance between the eye (3) ofpatient (2) and the color-scales (1,1/A) with rotating of the 12 setbolts. We can adjust the eyehole (6) to the patient's (2) eye (3) withmoving of the tillable left (13) and right part (14) which are been ableto rotate around the rotation axis (15).

In what follows we describe with more details the mechanism of theinvention according to the preferred device. The patient (2) moves theset of invention (4) in front of his eye (3) by the eyehole (6). The twoeyes see clearly the color-scale 1. The eye of patient which is lookingthrough the opening and the tube perceives the color-scale 1/A. Thecause of the tube (7) the eye 3 perceives the same color in a differentway as the eye 2 does. Than the patient is moving the color-scale 1 infront of the eye 2 until he will see the same dye perceived by his othereye (3). In that time we read the sign of this dye from the color-scale1/A named ‘NCS Index, edition 2’ and we compare it to a list made duringthe practical measures and find the assigned current blood-glucoselevel.

FIGS. 8 to 13 describe the invention in further detail from a variety ofperspectives.

Although the invention has been described with reference to certainspecific embodiments, various modifications thereof will be apparent tothose skilled in the art without departing from the spirit and scope ofthe invention as outlined in the claims appended hereto.

1. A device for measuring blood glucose level comprising: a box having acover that can be opened and closed and a side with two openings eachcovered with a transparent material further including at least two testcards arranged at specified distances and specified positions within thebox, and at least one illuminator in the box configured to generate adiffuse beam and positioned therein to illuminate the two test cardswherein light reflected from one of the test cards is directed to afirst of said openings and a diffuse beam reflected from the other testcard is directed through a tubular prism configured to make diffuselight parallel within 10° that is covered with a closing plate with afirst opening at one end while having a second opening aligned with asecond of said openings at the other end.
 2. Blood glucose levelmeasuring device as in claim 1, characterized by that a plurality ofpairs of test cards are fastened on sides of a regular polygonal prismthat can be rotated within the blood glucose level measuring device by aturn knob; and further a positioning spring holds the regular polygonalprism in position and a corresponding blood glucose level value isindicated on a dial of the turn-knob.
 3. Blood glucose level measuringdevice as in claim 2, characterized by that only a single pair of testcards is viewable through the openings in the box and the other pairs oftest cards are covered by two cover plates in order to eliminate theirdisturbing effects.
 4. Blood glucose level measuring device as in claim1, characterized by that one of said openings in the box is on a portionadjustable relative to the other opening.
 5. Blood glucose levelmeasuring device as in claim 1, characterized by that the illuminator isactuated by a micro switch mounted between two springs fastened to abase plate of the box.
 6. Blood glucose level measuring device as inclaim 1, characterized by that the diameter D1 of the first opening ofthe polygonal tubular prism is up to 2 mm, the diameter D2 of the secondopening of the polygonal tubular prism and the diameter D4 of the firstopening in the box are less than 10 mm each, and further the diameter D3of the tubular prism is greater than or equal to the diameter D2. 7.Blood glucose level measuring device as in claim 1, characterized bythat the distances between each opening in the box and the correspondingtest card are equal and the length of the tubular prism is longer than10mm.
 8. Blood glucose level measuring device as in claim 1,characterized by that the illuminator is a glow lamp controlled by apush-button switch or a rotating switch and the illumination is activefor a pre-determined time followed by a period where the illumination isdisabled for a specified time; the readiness of the device to beswitched on again is indicated by an indicator lamp; and furthercomprising a general switch to turn the device OFF and ON.
 9. Bloodglucose level measuring device as in claim 1, characterized by that itis provided with a voltage indicator connected to a battery.
 10. Bloodglucose level measuring device as in claim 1, further including abattery in electrical communication with the at least one illuminatorand a connector for recharging the battery.